﻿// Upgrade NOTE: replaced 'mul(UNITY_MATRIX_MVP,*)' with 'UnityObjectToClipPos(*)'

Shader "Custom/NormalMapTangentSpaceMat"
{
    Properties
    {
        _Color("Color Tint",Color) = (1,1,1,1)
        _MainTex("Main Tex",2D) = "white" {}
        _BumpMap("Bump Map",2D) = "bump" {}
        _BumpScale("Bump Scale",Float) = 1.0
        _Specular("Specular",Color) = (1,1,1,1)
        _Gloss("Gloss",Range(8.0,256)) = 20
    }
    SubShader
    {
        Pass
        {
            Tags {"LightMode"="ForwardBase"}
            
            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag
            #include "Lighting.cginc"
            
            fixed4 _Color;
            sampler2D _MainTex;
            float4 _MainTex_ST;
            sampler2D _BumpMap;
            float4 _BumpMap_ST;
            float _BumpScale;
            float4 _Specular;
            float _Gloss;
            
            struct a2v
            {
                float4 vertex:POSITION;
                float3 normal:NORMAL;
                float4 tangent:TANGENT;
                float4 texcoord:TEXCOORD;
            };
            
            struct v2f
            {
                float4 pos:SV_POSITION;
                float4 uv:TEXCOORD;
                float3 lightDir:TEXCOORD1;
                float3 viewDir:TEXCOORD2;
            };
            
            v2f vert(a2v v)
            {
                v2f o;
                o.pos = UnityObjectToClipPos(v.vertex);
                o.uv.xy = v.texcoord.xy * _MainTex_ST.xy + _MainTex_ST.zw;
                o.uv.zw = v.texcoord.xy * _BumpMap_ST.xy + _MainTex_ST.zw;
                
                TANGENT_SPACE_ROTATION;
                o.lightDir = mul(rotation,ObjSpaceLightDir(v.vertex)).xyz;
                o.viewDir = mul(rotation,ObjSpaceViewDir(v.vertex)).xyz;
                return o;
            }
            
            fixed4 frag(v2f i):SV_Target
            {
                fixed3 tangentLightDir = normalize(i.lightDir);
                fixed3 tangentViewDir = normalize(i.viewDir);
                fixed4 packedNormal = tex2D(_BumpMap,i.uv.zw);
                fixed3 tangentNormal;
                
                
                tangentNormal = UnpackNormal(packedNormal);
                tangentNormal.xy *= _BumpScale;
                tangentNormal.z = sqrt(1.0 - saturate(dot(tangentNormal.xy,tangentNormal.xy)));
                fixed3 albedo = tex2D(_MainTex,i.uv).rgb * _Color.rgb;
                fixed3 ambient = UNITY_LIGHTMODEL_AMBIENT.xyz * albedo;
                
                fixed3 diffuse = _LightColor0.rgb * albedo * max(0,dot(tangentNormal,tangentLightDir));
                fixed3 halfDir = normalize(tangentLightDir + tangentViewDir);
                
                fixed3 specular = _LightColor0.rgb * _Specular.rgb * pow(max(0,dot(tangentNormal,halfDir)),_Gloss);
                return fixed4(ambient + diffuse + specular,1.0);
            }
            
            
            ENDCG
        }   
    }
    Fallback "Specular"
}
